From 70317569c6dcd9809ed4a8c425777e653ec6ca08 Mon Sep 17 00:00:00 2001 From: Karen Arutyunov Date: Mon, 1 May 2017 18:24:31 +0300 Subject: Add hxx extension for headers --- build2/depdb | 201 ----------------------------------------------------------- 1 file changed, 201 deletions(-) delete mode 100644 build2/depdb (limited to 'build2/depdb') diff --git a/build2/depdb b/build2/depdb deleted file mode 100644 index abd2e20..0000000 --- a/build2/depdb +++ /dev/null @@ -1,201 +0,0 @@ -// file : build2/depdb -*- C++ -*- -// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd -// license : MIT; see accompanying LICENSE file - -#ifndef BUILD2_DEPDB -#define BUILD2_DEPDB - -#include -#include // strlen() - -#include -#include - -namespace build2 -{ - // Auxiliary dependency database (those .d files). Uses io_error and - // system_error exceptions to signal errors. - // - // This is a strange beast: a line-oriented, streaming database that can, at - // some point, be switched from reading to (over)writing. The idea is to - // store auxiliary/ad-hoc dependency information in the "invalidation" - // order. That is, if an earlier line is out of date, then all the - // subsequent ones are out of date as well. - // - // As an example, consider a dependency database for foo.o which is built - // from foo.cxx by the cxx.compile rule. The first line could be the rule - // name itself (perhaps with the version). If a different rule is now - // building foo.o, then any dep info that was saved by cxx.compile is - // probably useless. Next we can have the command line options that were - // used to build foo.o. Then could come the source file name followed by the - // extracted header dependencies. If the compile options or the source file - // name have changed, then the header dependencies are likely to have - // changed as well. - // - // As an example, here is what our foo.o.d could look like (the first line - // is the database format version and the last '\0' character is the end - // marker): - // - // 1 - // cxx.compile 1 - // g++-4.8 -I/tmp/foo -O3 - // /tmp/foo/foo.cxx - // /tmp/foo/foo.hxx - // /usr/include/string.h - // /usr/include/stdlib.h - // /tmp/foo/bar.hxx - // ^@ - // - // A race is possible between updating the database and the target. For - // example, we may detect a line mismatch that renders the target out-of- - // date (say, compile options in the above example). We update the database - // but before getting a chance to update the target, we get interrupted. On - // a subsequent re-run, because the database has been updated, we will miss - // the "target requires update" condition. - // - // If we assume that an update of the database also means an update of the - // target, then this "interrupted update" situation can be easily detected - // by comparing the database and target modification timestamps. - // - class depdb - { - public: - // Open the database for reading. Note that if the file does not exist, - // has wrong format version, or is corrupt, then the database will be - // immediately switched to writing. - // - depdb (const path&); - - // Return the modification time of the database. This value only makes - // sense while reading (in the write mode it will be timestamp_unknown). - // - timestamp - mtime () const {return mtime_;} - - // Update the database modification time in close() even if otherwise - // no modifications are necessary (i.e., the database is in the read - // mode and is at eof). - // - void - touch () {touch_ = true;} - - // Close the database. If this function is not called, then the database - // may be left in the old/currupt state. Note that in the read mode this - // function will "chop off" lines that haven't been read. - // - void - close (); - - // Read the next line. If the result is not NULL, then it is a pointer to - // the next line in the database (which you are free to move from). If you - // then call write(), this line will be overwritten. - // - // If the result is NULL, then it means no next line is available. This - // can be due to several reasons: - // - // - eof reached (you can detect this by calling more() before read()) - // - database is already in the write mode - // - the next line (and the rest of the database are corrupt) - // - string* - read () {return state_ == state::write ? nullptr : read_ ();} - - // Return true if the database is in the read mode and there is at least - // one more line available. Note that there is no guarantee that the line - // is not corrupt. In other words, read() can still return NULL, it just - // won't be because of eof. - // - bool - more () {return state_ == state::read;} - - bool - reading () {return state_ != state::write;} - - bool - writing () {return state_ == state::write;} - - // Write the next line. Note that this switches the database into the - // write mode and no further reading will be possible. - // - void - write (const string& l) {write (l.c_str (), l.size ());} - - void - write (const path& p) {write (p.string ());} - - void - write (const char* s) {write (s, std::strlen (s));} - - void - write (const char*, size_t); - - void - write (char); - - // Read the next line and compare it to the expected value. If it matches, - // return NULL. Otherwise, overwrite it and return the old value (which - // could also be NULL). This strange-sounding result semantics is used to - // detect the "there is a value but it does not match" case for tracing: - // - // if (string* o = d.expect (...)) - // l4 ([&]{trace << "X mismatch forcing update of " << t;}); - // - string* - expect (const string& v) - { - string* l (read ()); - if (l == nullptr || *l != v) - { - write (v); - return l; - } - - return nullptr; - } - - string* - expect (const path& v) - { - string* l (read ()); - if (l == nullptr || path::traits::compare (*l, v.string ()) != 0) - { - write (v); - return l; - } - - return nullptr; - } - - string* - expect (const char* v) - { - string* l (read ()); - if (l == nullptr || *l != v) - { - write (v); - return l; - } - - return nullptr; - } - - private: - void - change (bool flush = true); - - string* - read_ (); - - private: - timestamp mtime_; - std::fstream fs_; - - std::fstream::pos_type pos_; // Start of the last returned line. - string line_; - - enum class state {read, read_eof, write} state_; - bool touch_; - }; -} - -#endif // BUILD2_DEPDB -- cgit v1.1